A mobile number trace is a common search on the internet because these days more people then ever own cell phones and when you miss a call, all you are left with is a number.
Cell phone and mobile numbers are never printed in any type of phone books due to privacy reasons, making mobile trace sites the only way to get callers address, name, other numbers they may own, plus even civil and public records for running background checks.
There are many sites available that offer reverse phone searches, and out of these 7 of them offer high quality, confidential, guaranteed searches, plus free preliminary searches.
While these sites are all high quality, they do differ widely according to membership fees.
Therefore, out of the top 7, you only really need to look at the Top 3 sites for searching mobile numbers, and they are:

1. Phone Number 411
2. Reverse Phone Detective
3. Phone Number Scan

Which one you use depends on what you need.
If you have only one number to lookup, then reverse phone detective offers the cheapest deal for a one time report.
If you have many numbers to lookup, then use either phone number scan or phone number 411 to get an unlimited search, lifetime membership for a one time low fee (this is by far the best deal you can get on the net).
Memberships also give you access to government records so you can run background checks on any caller.
Unfortunately there are no free phone trace sites because you are getting access to normally private information and these sites paid phone companies for their data.
Start Tracing Any Number Now and Get The Best Deals: All you need to do is compare the best sites and try some free number searches to get caller location.